D3196: Physiological effects of plastic metabolism in the greater waxworms (Galleria mellonella)

The global accumulation of plastic waste continues to produce detrimental impacts to both wildlife and the environment. The application of biological organisms, notably Lepidopterans and Coleopterans, represents a promising field for bioremediation. Like a few other Lepidopterans, Galleria mellonella or the greater waxworm (Order Lepidoptera; Family Pyralidae) garnered recent attention due to its plastic degrading ability and have been labeled ‘plastivores’. Larval G. mellonella are voracious feeders capable of degrading low-density polyethylene presumably through a synergistic relationship with its microbiota. While it appears that plastic consumption correlates with maintenance of fat body lipid stores, the effects of plastic consumption on the metabolism of G. mellonella remains poorly understood. In a series of experiments, we first exposed fifth instar larvae to three plastic types (low-density polyethylene, polypropylene and polystyrene) for 6 days. We then used RNA sequencing to explore the molecular signature of each diet on the fat body. In addition, frass metabolites from each diet were identified through gas-chromatography and mass spectrometry (GC-MS), and microbial analysis of gut samples was performed through 16S sequencing. Results of this study provide evidence of profound physiological and metabolic effects of plastic diets on G .mellonella larvae, providing new avenues for the development of new in vitro plastic degradation strategies.